I was about to say something about sensory issues as well, same as tejas.

It could be he's sound sensitive, or his mind latches onto retitious sounds and can't block them out or shove them into the background, or integrate them into the rest of the sound that's happening.

I can't stand music that's turned up above a certain level, either (like Tejas' friend) - but that's because I get severe ringing in my ears afterward, and I can't hear anything else, either. Again, it's preference and physical overload.